The silver halide photographic light-sensitive material is used over a wide range of fields such as the field of platemaking and the field of medical diagnosis. As the application field extends and is intensified, requirements with respect to the development processing step necessary for forming an image are increased, in particular, a rapid and stable development processing is keenly demanded.
The silver halide photographic light-sensitive material is generally processed after exposure through steps of development, fixing and water washing. The black-and-white developer is commonly an alkaline solution containing a hydroquinone which is a dihydroxybenzene-base compound, as a developing agent, an aminophenol or 3-pyrazolidone as an auxiliary developing agent, and a sulfite. Other than the dihydroxybenzene-base compound, endiols such as an ascorbic acid is known to function as a developing agent and recently attracting an attention as a developing agent free of any ecological or toxicological problem as described above. For example, U.S. Pat. Nos. 2,688,549 and 3,826,654 disclose that an image can be formed under a high alkaline condition at a pH of at least 12 by using an ascorbic acid as a developing agent. However, these image forming methods are not satisfied in view of either rapidity or formation of a high contrast image.
Several attempts have been made to increase contrast in the development system using an ascorbic acid. For example, Zwicky, J. Phot. Sc., vol. 27, p. 185 (1979) discloses that when an ascorbic acid is used as a sole developing agent, a kind of lith effect is provided. However, this system is low in the contrast as compared with the hydroquinone development system. U.S. Pat. No. 3,022,168 discloses that the use of an ascorbic acid as a developing agent and of N-methyl-p-aminophenol as an auxiliary developing agent enables the formation of an image having a high contrast under a relatively low pH condition of from 8 to 9. However, these image forming methods are not satisfied in view of rapidity and in addition, not preferred in view of environmental concern because a large amount of boric acid must be contained in the developer. JP-B-49-46939 (the term "JP-B" as used herein means an "examined Japanese patent publication") and U.S. Pat. No. 5,474,879 disclose a system using a bis quaternary ammonium salt and an ascorbic acid in combination, however, although a development acceleration effect may be provided, almost no effect of increasing the contrast is obtained. JP-A-4-32838 (the term "JP-A" as used herein means an "unexamined published Japanese patent publication") describes a combination effect of a quaternary salt in the system using an ascorbic acid as a developing agent and a p-aminophenol or N-alkyl-p-aminophenol as an auxiliary developing agent, however, the image obtained is not satisfied in the contrast and the reference does not mention improvement in the progress of development at all. JP-A-5-88306 achieves high contrast by using an ascorbic acid as a sole developing agent and keeping the pH of 12.0 or more, however, the developer used is markedly deteriorated by air oxidation and has a large problem in view of stability.
Further, U.S. Pat. No. 3,730,727 discloses an example of a development system capable of providing high sensitivity and reduced in stains and fog with a specific developer using an ascorbic acid and a hydrazine derivative as main components, however, the reference does not mention improvement in the contrast at all.
It is known to process a light-sensitive material containing hydrazine with an ascorbic acid developer and this is disclosed in U.S. Pat. No. 5,236,816 and WO93/11456, however, either technique is insufficient in both the contrast and the rapidity. In the latter case, an amine is contained in the developer to achieve the contrast, and this is not preferred in view of environmental concern. A development processing method using an ascorbic acid preferred in view of toxicology, as a developing agent and capable of providing a high contrast image with rapidity, is being demanded, however, satisfactory contrast had not yet been obtained.